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Wind, birds and bats

It’s well known that cats kill many more birds than anything human beings have come up with, including cars and aeroplanes, but there’s an interesting survey of avian deaths from wind, fossil and nuclear plants: ‘Contextualizing avian mortality: A preliminary appraisal of bird and bat fatalities from wind, fossil-fuel, and nuclear electricity’, by Benjamin K. Sovacool in Energy Policy 37 (2009) 2241-2248.

Based on operating performance in the US and Europe, this study offers an approximate calculation for the number of birds killed per kWh generated for each systems. It estimates that wind farms and nuclear power stations are responsible each for between 0.3 - 0.4 fatalities per gigawatt-hour (GWh) of electricity, while fossil-fuelled power stations are responsible for about 5.2 fatalities/GWh. Although this is only as a preliminary assessment, the estimate means that wind farms killed approx. 7000 birds in the USA in 2006, but nuclear plants killed about 327,000 and fossil-fuelled power plants 14.5 million. However, the data is sparse, especially on bats, and the paper concludes that further study is needed.

Even so it provides a useful introduction. It notes that coal, oil, and natural gas-fired power plants induce avian deaths at various points throughout their fuel cycle: e.g. during coal mining, through collision and electrocution with operating plant equipment and transmission cables, and from poisoning and death caused by acid rain, mercury pollution and climate change. The scale of the direct impacts is quite surprising. e.g. an observation of 500m of power lines feeding a 400MW conventional power plant in Spain estimated that they electrocuted 467 birds and an additional 52 were killed in collisions with lines and towers over the course of two years. By comparison wind turbines seem quite benign (birds tend to avoid moving objects), although they too will have power grid links, and there were some early major problems with multiple bird strikes when wind farms were located in migratory paths e.g. in Southern Spain. Clearly sites like that should be avoided and we must also reduce casual impacts to the minimum possible, by sensitive location.

That is something the Royal Society for the Protection of Birds is keen to improve. It has come out with a positive approach to wind farm spatial planning, which it says can avoid problems and help ensure the development of wind power - which it backs as a response to climate change and energy security problems.

The RSPB report, ‘Positive Planning for Onshore Wind’, warns that ‘inappropriately sited wind farms can damage fragile wildlife and habitats, through habitat loss, mortality through collisions and a range of different disturbance effects’ but Ruth Davis, RSPB’s head of climate change policy, said ‘Left unchecked, climate change threatens many species with extinction. Yet, that sense of urgency is not translating into action on the ground to harness the abundant wind energy around us. This report shows that if we get it right, the UK can produce huge amounts of clean energy without time-consuming conflicts and harm to our wildlife. Get it wrong and people may reject wind power. That could be disastrous.’

It now wants to see a UK system of strategically chosen areas. That was the basis of Welsh “TAN8” planning policy introduced in 2005, which set out seven “Strategic Search Areas” that wind developers were to consider for wind farms. However, TAN8 has had mixed results so far, although the RSPB suggests there wasn’t enough consultation over the selection of the Strategic Search Areas. Scotland is now beginning to implement a “spatially explicit” new approach to onshore wind planning, via local development plans, but the RSPB report also highlights successful systems in Germany and Denmark- the RSPB commissioned a report from the Institute for European Environmental Policy, which found that wind farms were being developed rapidly on the Continent without harmful impacts on bird populations.

* A one year research programme carried out in the USA by the Bats and Wind Energy Cooperative, a partnership of the wind industry, government and conservation groups, at the Mountaineer windfarm in W. Virginia, and at the Meyersdale windfarm in Somerset County, Pennsylvania, found “substantial” mortality of bats at two U.S. windfarms, with a daily kill rate of 0.7 bats per turbine. At both windfarms, most bats were killed on nights when average wind speeds and power production were low, but while turbine blades were still moving at relatively high speeds, with fatalities increasing just before and after the passage of storm fronts and when bat activity was highest in the first two hours after sunset. Temporary close down during such periods is one possible remedial response.

Posted by Dave Elliott on July 11, 2009 12:52 PM | Permalink